24
Heatilator • Birmingham BIR50-B Installation Manual • 4059-701 • Rev G • 06/29/15
Roof radiation
shields
Allow a 1 in. (25 mm) air gap between
storm collar and chase top flashing
1/2 in. (13 mm) air space
established by spacers
1/2 in.
overhang
14 in. (345 mm)
diameter chimney
must extend at least
6 in. (152 mm) above
chase top flashing.
DuraChimney II
Pipe
1/2 in.
(13 mm)
Spacers for chase
top flashing
Chase Top
Flashing
Storm Collar
20 in. diameter
opening
Chimney Cap
Maintain 2 in. (51 mm)
clearance between
DuraChimney II and
chase enclosure
• Chase top shrouds may be field constructed where
permitted by regional building codes.
WARNING! Risk of Fire!
Shrouds must be constructed as
specified. Improper construction may overheat chase top.
NOTICE:
Some regional codes require an agency-Listed
shroud. Consult your local building officials.
5
Shrouds
• Hearth & Home Technologies supplies UL listed shrouds.
See your dealer for details.
A. Shroud Requirements
Figure 5.1 Shroud Requirements
Shrouds can either be field-fabricated or factory-fabri-
cated, but they must meet the requirements as specified
in these instructions. Shrouds must be constructed of a
minimum 24 ga (.024 in.) stainless steel, aluminized steel,
galvanized steel, or copper. Other materials may also be
used, such as brick, mortar, stucco, stone, etc. provided
they are completely non-combustible. Check with your
local building code authorities for any additional shroud
requirements. Shrouds must be able to be removed to al-
low chimney access to properly clean the chimney. Dura-
Chimney II installations which include the use of a shroud
must comply with the following requirements (Figure 5.1)
• DuraChimney II must maintain at least 2 in. (51 mm)
clearance from combustible materials.
• The chase enclosure must be ventilated.
• The chase top flashing or field-fabricated chase pan must
be used. Field-fabricated chase pans are acceptable if
they meet these requirements:
- Material must be 24 ga (.024 in) galvanized steel or
equivalent.
- Chase pan must have opening 3 in. (76 mm) larger
than outside diameter of chimney pipe with at least
a 1/2 in. (13 mm) upturned flange/collar.
- Chase pan must overhang chase by 1/2 in. (13 mm)
per side for proper air flow.
- Chase pan must have a 1 in. (25 mm) down turned
outside edge (weather protection).
